Moshe Zar lives in a castle-size home atop a hill in the West Bank, near the Palestinian city of Nablus. Although Zar, 65, is Jewish, his house isn't in a gated, guarded Israeli settlement, nor is it built in the suburb-in-the-desert style typical of those settlements. It is an enormous Arab-style house -- bigger than any building for miles around. Stone statues of roaring lions flank the doorway, and the driveway ends at a chain-link fence adorned with barbed wire. A giant antenna towers above the roof. No one is sure what it is for. (''Communications,'' Zar explains cryptically.) Zar doesn't hold any official position, although in practice, he functions as a sort of a Wild West-style vigilante mayor of his stretch of the West Bank, inspiring awe among many of the Jews there and fear among the Palestinians. Unlike most settlers, he doesn't have an army posting by his home; when disturbed, he has been known to lean his head out of a parapet and threaten to open fire on uninvited guests. He is a religious Zionist and a longtime friend of Prime Minister Ariel Sharon, and in the 1980's he achieved moderate fame for his role in the Jewish Underground, a terrorist group that planted bombs in the cars of Arab mayors and plotted to destroy the Dome of the Rock in Jerusalem. Israel captured the West Bank in the 1967 war; since 1979, Zar has been buying land in the territory from individual Palestinians. It is a controversial practice; some Palestinians who have sold land to Jews have been killed as collaborators. A number of Palestinians have taken Zar to court on claims that he falsified contracts. In 1983, a group of Palestinians attacked and stabbed Zar near his castle.

All over the West Bank in recent years, and particularly since the start of the second Palestinian intifada in September 2000, Israeli teenagers and young adults, almost all of them passionately religious, have been doing what Zar's grandchildren did -- claiming a small piece of land for their own. They are motivated sometimes by personal grief, sometimes by political anger, sometimes just by the youthful desire to be part of a daring adventure. Because they usually move onto hilltops, the Israeli media have taken to calling the most radical and colorful of these young settlers the ''hilltop youth.'' When these young settlers claim a new hill, they also claim the land around it, which in some cases Palestinians have been farming for many years. The new settlers don't seize the land in any official way; they simply uproot Palestinians' trees or shoot in the air at any Palestinian who comes close. About 70 of these small encampments, known in Israel as outposts, have been built in the last two years; together they represent a movement that intends to transform the West Bank, and the conflict in the Middle East, from the ground up.